It is previously known within mapping to generate and store a pixel and a height for each point on the ground. Resolutions that can be used are for example one meter or one decimeter on ground. The two data stored for each point describe texture and height in that point and referred to a suitable coordinate system. When producing these data it is necessary to be in possession of two different image recordings from somewhat different positions but generally rather close to the vertical line. These images can be displayed as orthophotos.
Stereo recording is per se previously known and it can for example be referred to U.S. Pat. No. 6,175,648 disclosing a multi image stereo processing method. A plurality of measurements are chosen or weighted into a common data base. Methods of obtaining height information from stereo recordings are inter alia discussed in our patent application PCT/EP2007/056780 filed Apr. 4, 2007.
One problem with this kind of data storing is that there is no possibility to store vertical surfaces or surfaces that are inclined inwards. A typical example of vertical surfaces is walls of houses but also other objects such as formations in the nature inclined inwards. When a wall of a house is shown from aside, the vertical surfaces are interpolated between roof and ground and no texture of the walls at all are available. Furthermore the height calculations are generally somewhat interpolated resulting in that the house walls or fronts are inclined outwards and due to that an image showing the front of a house does not look like the real house front.
An object with the present invention is to obtain a method enabling displaying of vertical surfaces or even slightly downwards and inwards inclined surfaces.